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i EVAX Project 2260-03 6 May 1991 1 T CONCLUSIONS j , 1. EVAX installed one vapor extraction/groundwater monitoring well (MW- 25) and one vapor extraction well (VW-26) on March 28, 1991 at Beacon F . Service Station 695 in Lodi, California. The base of the well casing of MW-25 was set at a depth of 77 feet below ground surface and groundwater level was at a depth of 66 feet. The base of the well casing of VW-26 a: was set at 59 feet below ground surface. I 2. Five soil samples, taken from the boring of MW-25 at depths of between 20.5 and 60.5 feet, were analyzed for TPHg and BTEX. Maximum concentrations of 4,800 ppm TPHg, 7.1 ppm B, 95 ppm T, 42 ppm E, and 220 ppm X were found in soils sampled at a depth of 40.5 feet. Minimum concentrations (i.e., <1.0 ppm TPHg, <0.005 ppm B, 0.007 ppm T, <0.005 ppm E, and 0.033 ppm X) were found in sails sampled near groundwater at a depth of 60.5 feet. 3. Four soil samples, taken from the boring of VW-26 at depths of between 30.5 and 64.5 feet, were also analyzed for TPHg and BTEX. No TPHg or BTEX was detected in the samples, except for a sample taken at a depth of 40.5 feet. Results of the 40.5-foot level sample werei: 580 ppm i - TPHg, <0.005 ppm B, 3.5 ppm T, <0.005 ppm E, and 14 ppm X. 4. The data suggests an attenuation in the hydrocarbon impact of soils with proximity to groundwater. 5. MW-25 was purged and sampled for groundwater on April 3, 1991. Laboratory analyses results indicated no detectable TPHg, BTEX, or TPHd in the groundwater sample. LIMITATIONS ka This report was prepared for Ultramar Inc. Evaluation of geological ! � conditions at the site for the purpose of this investigation was made from a limited number of borings and samples. Subsurface conditions may vary outward from areas drilled and sampled. Additional soil borings and analyses, and other subsurface study, can reduce the uncertainties commonly associ. ted with this type of environmental investigation. ss f ` tom, i - 6 - }